Chairs often include a base that supports a seat and/or a backrest. Examples of chairs, stools, and other types of seating devices and mechanisms utilized in seating devices may be appreciated from U.S. Pat. Nos. 8,764,117, 8,668,265, 8,663,514, 8,646,841, 8,480,171, 8,220,872, 8,216,416, 8,167,373, 8,157,329, 8,136,876, 8,029,060, 7,922,248, 7,887,131, 7,798,573, 7,478,878, 7,198,329, 6,997,511, 6,957,863, 6,880,886, 6,834,916, 6,824,218, 6,817,667, 5,997,087, 5,775,774, 5,683,139, 5,203,583, 5,112,103, 4,738,487, 4,652,050, 4,130,263, 3,312,437, and D664,779 and U.S. Pat. App. Pub. Nos. 2003/0168901, 2006/0006715, and 2008/0290712.